Broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines

Abstract

The embodiment of the invention provides a broadband filter integrated three-dimensional passive component based on vertical double-sided parallel-strip lines. First, second and third port feeder lines all consist of microstrip transmission lines; on a horizontal feeding panel, a through hole surface is connected with a plurality of first metal through holes; a grounding surface of a second layeris connected with the through hole surface through the first metal through holes; on a vertical plate, a filter is provided with a top-end filter branch; the filter and a quarter-wavelength impedancetransformer are connected, both consist of the vertical double-sided parallel-strip lines, and are symmetrically located on a third layer and a fourth layer respectively; a public ground surface is located between the third layer and the fourth layer; the top-end filter branch is connected with the public ground surface through second metal through holes; an impedance gradual change structure located on the fourth layer is respectively connected with the first port feeder line, the through hole surface and the filter. Therefore, the embodiment of the invention realizes a single passive component for balanced-unbalanced conversion from microstrip lines to the vertical double-sided parallel-strip lines; by further integration of a filter function, the integration degree is increased.

Description

technical field [0001] The invention relates to the field of radio frequency technology, in particular to a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines. Background technique [0002] The main function of the balun is to realize that when one input signal arrives at two output ports, the two output signals output are of equal amplitude and phase inversion, and vice versa. In addition, when the front and rear circuits of the balun do not match, it can also play the role of impedance transformation. In short, a balun converts a high-frequency signal from a single-ended unbalanced input to a double-ended balanced output with impedance matching. Therefore, as a three-port device, baluns are widely used in the balanced layout of radio frequency circuits, such as filters, power amplifiers and antenna feed networks, which directly affect the performance and quality of wireless communications. At present, baluns and filters, as ad...

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Problems solved by technology

[0004] However, at present, in this field, there is still a blank in the research on combining the vertical double-sided parallel strip line and the monomer balun and making it have a filtering function.

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